To damp vibrations and to absorb forces, bearings of a great variety of designs, mainly rubber bearings, are used in many different ways. In automotive engineering, they are used, for example, to mount parts of the wheel suspension or the drive assemblies of vehicles. It is known that depending on the application, the damping action of elastomeric damping members is additionally supported by hydraulic damping. To utilize the amortizing effect caused by the weight of liquid, chambers are provided in the elastomeric insert parts or rubber bodies of the chamber to receive a fluid damping agent. The chambers, whose size and position in the bearing depends on the required tuning, are connected to one another in a flow-carrying manner by one or more special channels, which are formed in special moldings that are additionally integrated in the bearing. Depending on the stress on the bearing, the damping agent is thus pressed from one chamber into another. Both bearings in which the hydraulic damping is used in respect to forces introduced radially into the bearing and bearings in which mainly the axial damping is supported by the damping liquid are known in this connection. Bearings in which the amortizing effect of the damping agent in the axial and radial directions is utilized are known as well.
Such a bearing, in which an elastomeric damping member is arranged between an inner part and an outer sleeve, is known from DE 691 01 803 T2. A first, fluid-filled chamber pair is arranged within the elastomeric damping member, and the two chambers belonging to it are located at the opposite ends of the bearing and frequency-dependent damping is brought about in the axial direction of the bearing. A second chamber pair with radially opposite chambers, which is provided for the radial damping, is arranged between this first chamber pair in the elastomeric damping member. The axially acting and the radially acting chambers are connected to one another via damping channels arranged in a channel carrier provided in the interior of the inner part. An essential drawback of this embodiment is the arrangement of the channel carrier in the interior of the inner part, as a result of which the damping channels, and consequently the damping characteristic can be varied to a very limited extent only. Moreover, the chambers of the respective chamber pairs as well as the chamber of the first chamber pair and that of the second chamber pair are arranged such that they are separated very far from one another in space.
Furthermore, hydraulically damping bearings with two chambers acting in one direction are known, in which the two chambers filled with hydraulic fluid can be connected to one another directly via a closable and releasable chamber wall opening, besides the connection via a damping channel, for a damping or stiffness that can be switched off or on depending on the operating state. Such a bearing is known, for example, from EP 0 173 273 A2, in which a chamber wall opening can be closed by a pneumatically controlled closing plate. The pneumatic cylinder acting as an actuating cylinder is arranged here outside the chambers and considerably increases the space needed for installing the bearing. Moreover, an additional sealing effort is necessary at the piston of the pneumatic cylinder, and this rather complicated arrangement is limited to two-chamber bearings.